@Riot: How would you feel about keeping current Abyssal in the game, but as a melee-only item?
This would enable champs like Diana and Kat to continue making good use of it, while keeping it off Liss, LeBlanc, etc. Basically, it keeps the item for champs that really like it as a first item against other AP mids, while keeping it off champions that only really like it as a second or third item for added safety.
I'll admit that as someone who really likes playing Diana mid, I'm concerned about losing current Abyssal.
EDIT: I'm not saying that PBE Abyssal shouldn't exist, but rather that it'd be neat if we could keep live Abyssal as a melee-only item, get PBE Abyssal as a new item, and rename and reflavor either item as necessary.